The 31-year-old Myers is 0-4 with a 3.52 ERA in 35 appearances this season. He has converted 19 of 21 save opportunities and has struck out 20 in 30 2/3 innings.

Myers is in the final year of his contract, but he has a vesting option that could guarantee his $10 million option next season if he appears in a certain amount of games. Rosenthal reported in June that the best estimate would be between 40 and 50 games, because the Astros reworked his contract when they converted him from a starter to closer before the season.

The move makes sense for the White Sox, who have the third-worst bullpen ERA in the American League. Rookie Addison Reed, the team's closer for most of the season, has a 4.24 ERA and has converted 15 of 18 save opportunities.